Getting to Mars will require conquering not only the 34 million miles between Earth and the red planet at their closest approach, but the human psyche as well.

The unglamorous reality of voyaging to Mars with present-day rockets is that it would require confining six humans in a small area for more than 17 months, with no escape and limited contact with the outside world.

Can you say “cabin fever”?

It worries the space agencies that may one day, later this century, play a role in sending humans to Mars.

So today, near Moscow, a hatch will close behind six men as they enter a small chamber — not to re-emerge for 520 days. The Mars-500 project, sponsored by Russia's Institute for Biomedical Problems, seeks to emulate the confinement and isolation of a human mission to Mars.

It's the longest study of its kind ever, and will include a simulated Mars landing as well as other features, such as a 20-minute communications delay with a “mission control” and limited showers to make the space travel experience as close to real as possible.

From data gathered during extended stays on Russia's Mir space station, the International Space Station and previous isolation tests, Dinges said psychological and behavioral issues could be the greatest challenge humans will face when they embark on years-long missions to Mars and other locations.

The crew entering the confinement chamber today includes three Russians, two Europeans and one Chinese.

America's contribution to the Russian-led project is limited to Dinges' research team, whose work is funded by the Houston-based National Space Biomedical Research Institute, a NASA-supported organization.

Psychological self-tests

Dinges' experiment, one of many on the project's schedule, has three parts: a test to measure attention and fatigue; unobtrusive video monitoring of participants' faces for 20 minutes a week; and wristwatch-like devices to measure their sleep cycles.

The psychological self-test will seek to determine whether cognitive ability and attention to detail decline over time. The computer facial recognition software will attempt to track moods, from happiness to depression. And the motion detector watch will see how sleep patterns change over time.

“We believe we will see changes in the behavior of the participants' brains that they themselves will not be aware of,” Dinges said.

Three showers a month

The crew will spend the next 250 days — until the beginning of February — in three hermetically sealed, roughly Winnebago-sized habitation modules connected to one another. They will shower once every 10 days, and e-mail will be their only contact with the outside world after the first 30 days.

After the “transit” to Mars, three of the crew members will land on the surface of Mars for 30 days, living in a module designed to simulate the planet's surface. Then the entire crew will spend another 240 days in their three habitat modules for the “return” home.

Only then will the hatch to the real world be opened again.

“It's not a large facility at all,” Dinges said. “The sleep areas are super tiny. As scientists it's difficult for us to imagine what it will be like to be sequestered in such a space for so long.”